Method for fabricating opening

ABSTRACT

The present invention provides a fabrication method of an opening. The method includes providing a substrate having a conductive region therein. Thereafter, a dielectric layer is formed over the substrate and then a stacked layer is formed on the dielectric layer. The stacked layer includes a patterned metal hard mask layer, a patterned silicon oxynitride layer and a patterned silicon oxide layer on the dielectric layer in sequence. Afterward, a first portion of the dielectric layer is removed using the stacked layer as a first mask to form a first opening that exposes a surface of the conductive region.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation application of and claims priority benefit ofpatent application Ser. No. 11/309,097, filed on Jun. 22, 2006. Theentirety of the above-mentioned patent application is herebyincorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for fabricating aninterconnect structure and an interconnect opening. More particularly,the present invention relates to a method for fabricating asingle-damascene structure, a dual-damascene structure, and an openingthereof.

2. Description of Related Art

With the advancement of semiconductor technologies, the dimensions ofsemiconductor devices continuously reduce to the deep sub-micronterritory. As the level of integration of integrated circuits increases,the surface of a chip is inadequate to accommodate all the requiredinterconnects. In order to accommodate the increase of interconnectsafter the miniaturization of semiconductor devices, the design of amultilevel interconnect is used in ultra large scale integrationcircuits (ULSI).

In general, the multilevel interconnection is formed using a damasceneprocess, which includes the single-damascene process or thedual-damascene process. Currently, the damascene process that involvesthe defining of a trench (or opening) in a dielectric layer requiresforming a titanium nitride layer on the dielectric layer first.Thereafter, a photoresist layer with a trench (or opening) pattern isformed over the titanium nitride layer. The trench (or opening) patternof the photoresist layer is then transferred to the titanium nitridelayer. Further using the titanium nitride layer with the trench (oropening) pattern as a hark mask, a trench (or opening) is then definedin the dielectric layer. Limited by the yellow light process, aplasma-enhanced oxide (PE-oxide) layer is typically formed on thetitanium nitride layer to increase the process window, wherein both thetitanium nitride layer and the PE-oxide layer serve as the hard masklayer in the damascene process.

However, there are problems still needed to be resolved in a damasceneprocess. For example, before defining the trench (or opening) in thedielectric layer, two etching steps are performed in order to define thetrench (or opening) pattern in the hard mask layer. The two etchingsteps include a first etching step and a second etching step. The firstetching step includes removing a portion of the PE-oxide layer until thesurface of the titanium nitride layer is exposed using the photoresistlayer as a mask. The second etching step includes etching a portion ofthe titanium nitride layer until the surface of the dielectric layer isexposed. Accordingly, the conventional damascene process requiresperforming multiple steps, and thus a longer cycle time is resulted.

SUMMARY OF THE INVENTION

Accordingly, the present invention at least provides a method forfabricating an opening, in which the process step is simplified and thecycle time is conserved.

The present invention provides a fabrication method of an opening. Themethod includes providing a substrate having a conductive regiontherein. Thereafter, a dielectric layer is formed over the substrate andthen a stacked layer is formed on the dielectric layer. The stackedlayer includes a patterned metal hard mask layer, a patterned siliconoxynitride layer and a patterned silicon oxide layer having the samepattern on the dielectric layer in sequence. Afterward, a first portionof the dielectric layer is removed using the stacked layer as a firstmask to form a first opening that exposes a surface of the conductiveregion.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the step of forming the stackedlayer includes forming sequentially a metal hard mask layer, a siliconoxynitride layer and a silicon oxide layer on the dielectric layer.Thereafter, a first bottom antireflection layer and a patternedphotoresist layer on the silicon oxide layer are formed sequentially.After this, the metal hard mask layer, the silicon oxynitride layer, theoxide layer and the first bottom antireflection layer that are notcovered by the patterned photoresist layer are removed in a singleprocess step until a part of a surface of the dielectric layer isexposed so as to form the patterned metal hard mask layer, the patternedsilicon oxynitride layer, the patterned silicon oxide layer and apatterned first bottom antireflection layer. Afterward, the patternedphotoresist layer and the patterned first bottom antireflection layerare removed.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the patterned hard mask layerincludes, but not limited to, tantalum, tantalum nitride, titanium,titanium nitride, tungsten and tungsten nitride.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the first opening is asingle-damascene opening.

According to an embodiment of the present invention, the fabricationmethod of the above-mentioned opening further includes before the firstportion of the dielectric layer is removed, forming a second opening inthe dielectric layer, so that a dual damascene opening constructs thefirst opening after the step of removing the first portion of thedielectric layer is performed.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the step of forming the secondopening in the dielectric layer includes forming a second patternedphotoresist layer over the substrate to expose a surface of a secondportion of the dielectric layer and to cover the patterned oxide layer,the patterned silicon oxynitride layer and a third portion of thedielectric layer. Thereafter, the second portion of the dielectric layeris removed to form the second opening in the dielectric layer using thesecond patterned photoresist layer as a second mask. After this, thesecond patterned photoresist layer is removed.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, before the second patternedphotoresist layer is formed, a second bottom antireflection layer isfurther formed over the substrate.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the stacked layer has a trenchpattern.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the conductive region is aconductive line.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the dielectric layer is formedwith a material including a low dielectric constant material.

The present invention also provides a fabrication method of an opening.The method includes providing a substrate having a conductive regiontherein. Thereafter, a dielectric layer over the substrate is formed andthen a metal hard mask layer and a silicon oxynitride layer are formedsequentially over the dielectric layer. After this, a surface propertyalteration process is performed to form a modified layer on the siliconoxynitride layer. Afterword, the modified layer, the silicon oxynitridelayer and the metal hard mask layer are patterned to form a stackedlayer including a patterned modified layer, a patterned siliconoxynitride layer and a patterned metal hard mask layer having the samepattern. A first portion of the dielectric layer is removed to form afirst opening that exposes a surface of the conductive region using thestacked layer as a first mask.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the surface property alterationprocess includes a plasma process.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the step of forming the stackedlayer includes forming sequentially a metal hard mask layer and asilicon oxynitride layer on the dielectric layer before the surfaceproperty alteration process is performed to form the modified layer onthe silicon oxynitride layer. A first bottom antireflection layer and apatterned photoresist layer are formed sequentially on the modifiedlayer. Afterward, the metal hard mask layer, the silicon oxynitridelayer, the modified layer and the first bottom antireflection layer thatare not covered by the patterned photoresist layer are removed in asingle process step until a part of a surface of the dielectric layer isexposed so as to form the patterned metal hard mask layer, the patternedsilicon oxynitride layer, the patterned silicon oxide layer and apatterned first bottom antireflection layer. The patterned photoresistlayer and the patterned first bottom antireflection layer are removed.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the patterned hard mask layerincludes, but not limited to, tantalum, tantalum nitride, titanium,titanium nitride, tungsten and tungsten nitride.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the first opening is asingle-damascene opening.

According to an embodiment of the present invention, the fabricationmethod of the above-mentioned opening further includes before the firstportion of the dielectric layer is removed, forming a second opening inthe dielectric layer, so that a dual damascene opening constructs thefirst opening after the first portion of the dielectric layer isremoved.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the step of forming the secondopening in the dielectric layer includes forming a second patternedphotoresist layer over the substrate to expose a surface of a secondportion of the dielectric layer and to cover the patterned oxide layer,the patterned silicon oxynitride layer and a third portion of thedielectric layer. After this, the second portion of the dielectric layeris removed to form the second opening in the dielectric layer using thesecond patterned photoresist layer as a second mask. Thereafter, thesecond patterned photoresist layer is removed.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, before the second patternedphotoresist layer is formed, a second bottom antireflection layer isfurther formed over the substrate.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the stacked layer has a trenchpattern.

According to an embodiment of the present invention, in the fabricationmethod of the above-mentioned opening, the conductive region is aconductive line.

According to the fabrication method and the damascene structure of thepresent invention, the plasma enhanced oxide layer (PE-oxide) in theprior art is replaced by the silicon oxynitride layer. Moreover, beforethe step of defining the trench in the dielectric layer, only a singleetching step is required to define the trench (or opening) pattern inthe hard mask layer. Therefore, the process step of the fabricationmethod of the present invention is simplified and the cycle time isreduced.

Several exemplary embodiments of the invention will now be described indetail with reference to the accompanying drawings. It is to beunderstood that the foregoing general description and the followingdetailed description of preferred purposes, features, and merits areexemplary and explanatory towards the principles of the invention onlyand are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIGS. 1A to 1D are schematic diagrams showing the method for fabricatinga single-damascene opening according to one embodiment of the presentinvention.

FIGS. 2A to 2G are schematic diagrams showing the method for fabricatinga dual-damascene opening according to one embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention. It is to be understood that both theforegoing general description and the following detailed description areexemplary, and are intended to provide further explanation of theinvention as claimed.

FIGS. 1A to 1D are schematic diagrams showing the method for fabricatinga single-damascene opening according to one embodiment of the presentinvention.

Referring to FIG. 1A, a substrate 100 is provided, wherein a conductiveline 102 is already formed in the substrate 100. The conductive line 102is formed with copper, for example.

Still referring to FIG. 1A, a barrier layer 104, a dielectric layer 106,a metal hard mask layer 108, a silicon oxynitride layer 110, a bottomantireflection layer 112 and a patterned photoresist layer 114 aresequentially formed on the substrate 100.

The material of the photoresist layer 114 includes silicon nitride orother suitable materials. The photoresist layer 114 is formed bychemical vapor deposition, for example. The barrier layer 104 serves toprevent the oxidation of the copper surface and the diffusion of copperto the dielectric layer 106. The dielectric layer 106 is, for example, alow dielectric constant dielectric layer which is formed with a lowdielectric constant material including inorganic materials, such ashydrogen silsesquioxane (HSQ), fluronated silicon glass (FSG), etc., ororganic materials, such as fluorinated poly(arylene ether) (Flare),aromatic hydrocarbons (SILK), poly-arylethers (parylene), etc. Thedielectric layer 106 is formed by chemical vapor deposition, forexample. In one embodiment, the dielectric layer 106 is constituted witha low dielectric constant dielectric layer and an insulation layer,wherein the insulation layer can also serve as a chemical mechanicalpolishing (CMP) stop layer to prevent the dielectric layer 106 frombeing polished during the CMP process. The material of the metal hardmask layer 108 includes tantalum, tantalum nitride, titanium, titaniumnitride, tungsten or tungsten nitride, and the metal hard mask layer 108is formed by chemical vapor deposition. The bottom antireflection layeris an organic bottom antireflection layer or inorganic bottomantireflection layer. The inorganic antireflection layer is formed bychemical vapor deposition, for example. The material of the inorganicantireflection layer includes, but not limited to, a non-crystallinephase carbon film, silicon nitride, silicon oxynitride or titaniumnitride, etc.

In one embodiment, after forming the silicon oxynitride layer 110 andbefore forming the bottom antireflection layer 112, a silicon oxidelayer (not shown) can also form on the silicon oxynitride layer 110 sothat the refractive index (n) and the dielectric constant (k) of thesilicon oxynitride layer 110 remain unchanged over time.

In another embodiment, after forming the silicon oxynitride layer 110,and before forming the bottom antireflection layer 112, a surfaceproperty alteration process can perform on the silicon oxynitride layer110 to form an oxide layer (not shown) on the silicon oxynitride layer110 in order to maintain the refractive index and the dielectricconstant of the silicon oxynitride layer 110 from varying over time. Thesurface property alteration process includes a plasma process using anoxygen containing gas.

More particularly, the silicon oxynitride layer 110 can reduce thereflective light of the underlying reflective material (metal hard masklayer 108). Consequently, the photolithograph process is improved.

Referring to FIG. 1B, the bottom antireflection layer 112, the siliconoxynitride layer 110 and the metal hard mask layer 108 that are notcovered by the patterned photoresist layer 114 are directly removeduntil a part of the surface of the dielectric layer 106 is exposed. Inother words, the removal of the bottom antireflection layer 112, thesilicon oxynitride layer 110 and the metal hard mask layer 108 that arenot covered by the patterned photoresist layer 114 is completed byperforming one etching process. In essence, only a single etchingprocess is performed.

Continuing to FIG. 1C, the patterned photoresist layer 114 and thebottom antireflection layer 112 are removed, for example, by an etchingprocess. Thereafter, the silicon oxynitride layer 110 and the metal hardmask layer 108 are used as a mask to remove a portion of the dielectriclayer 106 104 to form a damascene opening 116 that exposes the surfaceof the conductive line 102. Removing the portion of the dielectric layerand the portion of the barrier layer is accomplished by removing thedielectric layer that is not covered by the silicon oxynitride layer 110and the metal hard mask layer 108. The dielectric layer 106 is removedby, for example, performing an etching process. Thereafter, the exposedbarrier layer 104 is removed, for example, by an etching process.

After this, as shown in FIG. 1D, the damascene opening 116 is filledwith a conductive layer 118. Further using the CMP process to remove theexcess metal, a single-damascene structure is formed. The material ofthe conductive layer 118 is metal or polysilicon, for example.

It is worthy to note that before the step of defining an opening in thedielectric layer, only a single etching step is performed to define theopening in the hard mask layer. Therefore, not only the process step issimplified, the cycle time is greatly conserved.

The single-damascene structure formed according the method of thefabrication is disclosed as follows. Since the materials of the parts ofthe damascene structure have been disclosed in the above embodiment,they will not be reiterated herein.

Still referring to FIG. 1D, the single-damascene structure includes thesubstrate 100, the barrier layer 104, the dielectric layer 106, themetal hard mask layer 108, the silicon oxynitride layer 110 and theconductive layer 119. The conductive line 102 is disposed in thesubstrate 100. The barrier layer 104 is disposed on the substrate 100,and the dielectric layer 106 is disposed on the barrier layer 104. Themetal hard mask layer 108 is disposed on the dielectric layer 106, andthe silicon oxynitride layer 110 is disposed on the metal hard masklayer 108. The damascene opening 116 exposing a part of the surface ofthe conductive line 102 is configured in the silicon oxynitride layer110, the metal hard mask layer 108, the dielectric layer 106 and thebarrier layer 104. The conductive layer 118 is disposed in the damasceneopening 116.

In one embodiment, single-damascene structure further can include asilicon oxide layer (not shown), disposed on the silicon oxynitridelayer 112.

In another embodiment, the single-damascene structure can include anoxide layer (not shown), disposed on the silicon oxynitride layer 112.The oxide layer is formed by performing a plasma process on the siliconoxynitride layer 112 to alter the surface property of silicon oxynitridelayer 112. The above silicon oxide layer and oxide layer can serve tomaintain the refractive index and the dielectric constant of the siliconoxynitride layer from changing over time.

FIGS. 2A to 2G are schematic diagrams showing the method for fabricatinga dual-damascene opening according to one embodiment of the presentinvention. The same reference numbers are used in FIGS. 1A to 1D andFIGS. 2A to 2G to refer to the same or like parts.

Referring to FIG. 2A, a substrate 100 is provided, wherein a conductiveline 102 is already formed in the substrate 100. The conductive line 102is formed with copper, for example.

Still referring to FIG. 2A, a barrier layer 104, a dielectric layer 106,a metal hard mask layer 108, a silicon oxynitride layer 110, a bottomantireflection layer 112 and a patterned photoresist layer 114 aresequentially formed on the substrate 100.

In one embodiment, after forming the silicon oxynitride layer 110 andbefore forming the bottom antireflection layer 112, a silicon oxidelayer (not shown) can also form on the silicon oxynitride layer 110 sothat the refractive index (n) and the dielectric constant (k) of thesilicon oxynitride layer 110 remain unchanged over time.

In another embodiment, after forming the silicon oxynitride layer 110,and before forming the bottom antireflection layer 112, a surfaceproperty alteration process is performed on the silicon oxynitride layer110 to form an oxide layer (not shown) on the silicon oxynitride layer110 in order to maintain the refractive index and the dielectricconstant of the silicon oxynitride layer 110 from changing over time.The surface property alteration process includes a plasma process usingan oxygen containing gas.

As shown in FIG. 2B, the bottom antireflection layer 112, the siliconoxynitride layer 112 and the metal hard mask layer 108 not covered bythe patterned photoresist layer 114 are removed in a single process stepto form a trench 120 that exposes the surface of a part of thedielectric layer 106.

Similarly, the silicon oxynitride layer 110 and the metal hard masklayer 108 are removed under the same etching condition. Therefore,unlike the conventional practice in which the metal hard mask layer andthe overlying layer have different properties and are removed underdifferent etching conditions, the process step of the present inventionis greatly simplified and the cycle time is conserved to increase theyield.

Thereafter, as shown in FIG. 2C, the patterned photoresist layer 114 andthe bottom antireflection layer 112 are removed. A patterned photoresistlayer 122 is then formed over the substrate 100 to cover the siliconoxynitride layer 110 and a part of the dielectric layer 106. Thispatterned photoresist layer 122 has an opening pattern 123 therein.

In one embodiment, before forming the patterned photoresist layer 122, abottom antireflection layer (not shown) is formed over the substrate 100to cover the silicon oxynitride layer 110 and the dielectric layer 106.

Referring to FIG. 2D, using the patterned photoresist layer 122 as amask, a portion of the dielectric layer 106 is removed to form anopening 124 in the dielectric layer 106.

Continuing to FIG. 2E, the patterned photoresist layer 122 is removed,for example, by performing an etching process.

Thereafter, as shown in FIG. 2F, the silicon oxynitride layer 110 andthe metal hard mask layer 108 are used as a mask, and a portion of thedielectric layer 106 104 are removed until the surface of the conductiveline 102 is exposed to form a trench 121 and an opening 125. The trench121 and the opening 125 serve as a dual-damascene opening 126.

Continuing to FIG. 2G, the dual-damascene opening 126 is filled with aconductive layer 128. Further using a CMP process to remove the excessmetal, a conductive line is formed in the trench 121 and a plug isformed in the opening 125, wherein the conductive line and the plugconstitute a dual damascene structure. The material of the conductivelayer 128 includes, but not limited to, a metal material or polysilicon.

The dual-damascene structure formed according the fabrication method ofthe present invention is disclosed as follows. Since the materials forthe parts of the damascene structure have been disclosed in the aboveembodiment, they will not be reiterated herein.

Referring again to FIG. 2G, the dual-damascene structure mainly includesthe substrate 100, the barrier layer 104, the dielectric layer 106, themetal hard mask layer 108, the silicon oxynitride layer 110 and theconductive layer 128. The conductive line 102 is configured in thesubstrate 100. The barrier layer 104 is disposed on the substrate 100,and the dielectric layer 106 is disposed on the barrier layer 104. Themetal hard mask layer 108 is disposed on the dielectric layer 106. Thesilicon oxynitride layer 110 is disposed on the metal hard mask layer108. The dual-damascene opening 126 exposing a part of the surface ofthe conductive line 102 is configured in the silicon oxynitride layer110, the metal hard mask layer 108 and the dielectric layer 106. Theconductive layer 128 is disposed in the damascene opening 126.

In one embodiment, the dual-damascene structure further includes asilicon oxide layer (not shown), disposed on the silicon oxynitridelayer 112.

In another embodiment, the dual-damascene structure includes an oxidelayer (not shown), disposed on the silicon oxynitride layer 112. Theoxide layer is formed by performing a plasma process on the siliconoxynitride layer 112 to alter the surface property of the siliconoxynitride layer 112. The above silicon oxide layer and oxide layerserve to maintain the refractive index and the dielectric constant ofthe silicon oxynitride layer from altering over time.

According to the present invention, before defining a trench (oropening) in the dielectric layer, only a single etching step isperformed to define a trench (or opening) pattern in the hard masklayer. Not only the process step is simplified, the cycle time isconserved. Further, the silicon oxynitride layer can absorb thereflective light from the metal mask layer to enhance thephotolithograph process.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

1. A fabrication method of an opening, the method comprising: providinga substrate having a conductive region therein; forming a dielectriclayer over the substrate; forming a patterned metal hard mask layer, apatterned silicon oxynitride layer and a patterned silicon oxide layerhaving the same pattern on the dielectric layer to form a stacked layer;and removing a first portion of the dielectric layer to form a firstopening that exposes a surface of the conductive region using thestacked layer as a first mask.
 2. The method of claim 1, wherein thestep of forming the patterned metal hard mask layer, the patternedsilicon oxynitride layer and the patterned silicon oxide layer on thedielectric layer comprises: forming sequentially a metal hard masklayer, a silicon oxynitride layer and a silicon oxide layer on thedielectric layer; forming sequentially a first bottom antireflectionlayer and a patterned photoresist layer on the silicon oxide layer;removing the metal hard mask layer, the silicon oxynitride layer, theoxide layer and the first bottom antireflection layer that are notcovered by the patterned photoresist layer in a single process stepuntil a part of a surface of the dielectric layer is exposed so as toform the patterned metal hard mask layer, the patterned siliconoxynitride layer, the patterned silicon oxide layer and a patternedfirst bottom antireflection layer; and removing the patternedphotoresist layer and the patterned first bottom antireflection layer.3. The method of claim 1, wherein the patterned hard mask layer isformed with a material selected from the group consisting of tantalum,tantalum nitride, titanium, titanium nitride, tungsten and tungstennitride.
 4. The method of claim 1, wherein the first opening is asingle-damascene opening.
 5. The method of claim 1, further comprisingbefore the step of removing the first portion of the dielectric layer isperformed, forming a second opening in the dielectric layer, so that adual damascene opening constructs the first opening after the step ofremoving the first portion of the dielectric layer is performed.
 6. Themethod of claim 5, wherein the step of forming the second opening in thedielectric layer comprising: forming a second patterned photoresistlayer over the substrate to expose a surface of a second portion of thedielectric layer and to cover the patterned oxide layer, the patternedsilicon oxynitride layer and a third portion of the dielectric layer;and removing the second portion of the dielectric layer to form thesecond opening in the dielectric layer using the second patternedphotoresist layer as a second mask; and removing the second patternedphotoresist layer.
 7. The method of claim 6, wherein before the step offorming the second patterned photoresist layer is performed, a secondbottom antireflection layer is further formed over the substrate.
 8. Themethod of claim 5, wherein the stacked layer has a trench pattern. 9.The method of claim 1, wherein the conductive region is a conductiveline.
 10. The method of claim 1, wherein the dielectric layer is formedwith a material comprising a low dielectric constant material.
 11. Afabrication method of an opening, the method comprising: providing asubstrate having a conductive region therein; forming a dielectric layerover the substrate; forming sequentially a metal hard mask layer and asilicon oxynitride layer over the dielectric layer; performing a surfaceproperty alteration process to form a modified layer on the siliconoxynitride layer; patterning the modified layer, the silicon oxynitridelayer and the metal hard mask layer to form a patterned modified layer,a patterned silicon oxynitride layer and a patterned metal hard masklayer having the same pattern so as to form a stacked layer; andremoving a first portion of the dielectric layer to form a first openingthat exposes a surface of the conductive region using the stacked layeras a first mask.
 12. The method of claim 11, wherein the surfaceproperty alteration process comprises a plasma process.
 13. The methodof claim 11, wherein the step of patterning the modified layer, thesilicon oxynitride layer and the metal hard mask layer comprises:forming sequentially a metal hard mask layer and a silicon oxynitridelayer on the dielectric layer before the step of performing the surfaceproperty alteration process is conducted; forming sequentially a firstbottom antireflection layer and a patterned photoresist layer on themodified layer; removing the metal hard mask layer, the siliconoxynitride layer, the modified layer and the first bottom antireflectionlayer that are not covered by the patterned photoresist layer in asingle process step until a part of a surface of the dielectric layer isexposed so as to form the patterned metal hard mask layer, the patternedsilicon oxynitride layer, the patterned silicon oxide layer and apatterned first bottom antireflection layer; and removing the patternedphotoresist layer and the patterned first bottom antireflection layer.14. The method of claim 11, wherein the patterned hard mask layer isformed with a material selected from the group consisting of tantalum,tantalum nitride, titanium, titanium nitride, tungsten and tungstennitride.
 15. The method of claim 11, wherein the first opening is asingle-damascene opening.
 16. The method of claim 11, further comprisingbefore the step of removing the first portion of the dielectric layer isperformed, forming a second opening in the dielectric layer, so that adual damascene opening constructs the first opening after the step ofremoving the first portion of the dielectric layer is performed.
 17. Themethod of claim 16, wherein the step of forming the second opening inthe dielectric layer comprising: forming a second patterned photoresistlayer over the substrate to expose a surface of a second portion of thedielectric layer and to cover the patterned oxide layer, the patternedsilicon oxynitride layer and a third portion of the dielectric layer;and removing the second portion of the dielectric layer to form thesecond opening in the dielectric layer using the second patternedphotoresist layer as a second mask; and removing the second patternedphotoresist layer.
 18. The method of claim 17, wherein before the stepof forming the second patterned photoresist layer is performed, a secondbottom antireflection layer is further formed over the substrate. 19.The method of claim 16, wherein the stacked layer has a trench pattern.20. The method of claim 11, wherein the conductive region is aconductive line.